Note: How to Choose the Right Sewer Hose for your ApplicationChoosing a sewer hose depends on how often you go RVing and the mil thickness of the hose. For instance, 1 mil is equivalent to .001 inches. If you are a full time RVer you may want to choose one that has a higher mil thickness and is heavy duty (currently the highest 26 mil), versus someone that occasionally RVs', they can go with a more standard smaller mil size (currently the lowest 8 mil).